In the design of equipment for sorting discrete bruisable articles, particularly for sorting pieces of fruit (e.g. apples or pears) by weight, color, or other property, additional care is being taken to handle the fruit gently so as to reduce bruising. While prior art sorters, such as disclosed in U.S. Pat. Nos. 4,595,091 and 4,262,807 do not necessarily handle the fruit roughly, there is a perception in the trade that the fruit should be handled more gently and therefore manufacturers of fruit sorting equipment are attempting to respond to this perception. This is especially so since fewer and fewer packers are using ALAR (diminozide) to treat the fruit. ALAR gives the fruit additional toughness and protection against bruising, and if not utilized, gentler handling is desirable.
The two major areas where bruising can occur in conventional article sorting equipment are in the transfer of the pieces of fruit from a singulating mechanism to the conveyance cups (which then subsequently pass over a load cell or the like), and in the discharge of the pieces of fruit at a discharge section. Often the discharge is handled so that the piece of fruit is discharged in the direction of conveyance so that it has a large velocity component in that direction. It is more desirable so as to minimize bruising to discharge the article without a significant velocity component in the direction of conveyance by moving it generally perpendicular to the direction of conveyance. While there have been a number of procedures for effecting this in the past, such as shown in U.S. Pat. Nos. 4,595,091 and 4,586,613, oftentimes a larger discharge force than desirable has been imparted to the article either due to impacting of the article with a sidewardly moving element, or because the angle of tilt necessary to discharge the article was relatively large (e.g. more than about 30.degree.).
According to the present invention, an article sorting apparatus and method are provided which seek to minimize the bruising of fruit during sorting thereof according to fruit property (particularly weight, but also possibly color, or other property thereof) while providing a simple and economical arrangement.
The apparatus according to the invention includes a continuous conveying chain elongated in a dimension of elongation with a plurality of discrete article supporting elements (cups) connected to the chain for linear movement with it, and for pivotal movement with respect to the chain about an axis generally parallel to the dimension of elongation. A plurality of stations are provided for the continuous conveying chain and article supporting elements, including a self-singulating section in which the articles are singulated onto the supporting elements, an article property determining section through which the articles are carried by the supporting elements and properties thereof sensed, and a discharge section in which the articles are selectively discharged at a plurality of spaced distinct locations depending upon the properties thereof sensed in the article property determining section. The self-singulating section may comprise a pair of elongated strip brushes, one mounted on either side of the conveying cups (article supporting elements). The strip brushes are mounted so that they are disposed at an angle with respect to the linear direction of movement of the conveying cup so as to facilitate gentle individual movement of apples or like discrete bruisable objects into the cups. The strip brushes preferably comprise brushes having synthetic material bristles with an unsupported length of about 1/2 inch-11/2 inches (e.g., about 1 inch), the synthetic material preferably being nylon.
The supporting elements preferably comprise plastic cups, each having a shallow depression on a top face. The depression is deep enough to positively hold the article for property determination and conveyance, but shallow enough so that the cup need be tilted only a small amount about its axis to effect discharge with minimal bruising; e.g. a generally conically shaped depression may be provided. The depression is provided between front, rear, and two side edges. The front and rear edges are longer than the side edges, and the depression has an effective greater angle of inclination at at least a portion thereof from the bottom to the front and rear edges than from the bottom to the side edges. For example, the effective angle of inclination with regard to the front and rear edges is about 30.degree., while with respect to the side edges is about 20.degree.. In this way, the apples are more positively held in place in the direction of conveyance than they are in the direction perpendicular to the direction of conveyance (that is, the direction of discharge).
The individual conveying cups of the apparatus according to the invention, which are connectable to the transporting chain, are made of two different plastic bodies. A first body is of a first plastic material, such as Delrin or UHMW, which has dimensional stability, and includes a means for connecting the body to a transporting chain. The second body is of a second plastic which need not have dimensional stability, and is of less expensive and softer material than the first material (e.g., EVA). The second body is connected to the first body and extends therefrom in a dimension opposite the connecting means, and has an exterior contour for holding an apple or like discrete bruisable element so that it will not inadvertently move out of the body. The cup also preferably comprises a trip tab integral with the first body and of the first material and extending downwardly from the first body, oppositely to the portion thereof to which the second body is connected. The cup according to the invention may be constructed by injection molding wherein the first body is injection molded in a first mold, the first body is then inserted in a second mold, and the second body is formed in the second mold, around the first body so that the first body holds it in place. The formed cup is remove from the second mold, and it is cooled. The first body is formed so that after it cools due to the natural warpage thereof, the first body holds the second body more securely than prior to natural warpage.
The invention also comprises a bruisable discrete element transfer mechanism. This mechanism comprises: a first transporting means for transporting the bruisable element in a first direction at a first level; a second transporting means for transporting the bruisable element in a second direction and/or second level, different than said first direction and/or level; a brush having a shaft rotatable about an axis, and adjacent the first transporting means, and having bristles extending from the shaft positioned adjacent the first level; means for rotating the shaft so that the brush bristles have a tangential direction of movement adjacent the first level in the first direction; and means for moving the bruisable element from the first transporting means to the brush so that the bruisable element is engulfed by the brush bristles and moves through the bristles toward the shaft so that the brush transfers the bruisable element from the first transporting means to the second transporting means. The bristles preferably have a length of about 4-6 inches, and frayed ends, and are of polyethylene. The axis of rotation of the brush shaft is substantially horizontal, and the second direction and level are both different than the first direction and level. The second level is preferably below the first level by a distance approximately equal to the radius of the brush. Finger means extend into the brush bristles at approximately the second level for stripping the bruisable element from the brush and facilitating deposit thereof in operative association with the second transporting means.
The invention further contemplates a method of handling bruisable articles, such as pieces of fruit without diminozide, to minimize the bruising action of handling. The method comprises the steps of: (a) While continuously conveying the pieces of fruit in a direction of conveyance, sequentially (a1) singulating, (a2) weighing, and (a3) selectively discharging the pieces depending upon the weights thereof, utilizing a continuous mechanism so that there is no necessity for transferring the pieces from one conveyance mechanism to another. And, (b) practicing said step (a3) by discharging the pieces of fruit so that the velocity component in the direction of conveyance is gradually and gently reduced after discharge to a low level, and then the pieces are carried away in a direction generally perpendicular to the direction of conveyance.
It is the primary object of the present invention to provide for the simple and effective sorting of discrete bruisable articles, such as pieces of fruit not treated with diminozide, with a minimum of bruising. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.